ON A PECULIAR DWARF MUTANT DM1 ORIGINATED FROM M-TYPE-VAR. (MURASE) IN ESCHERICHIA AND SALMONELLA
1968 Volume 28 Issue 12 Pages 752-760
Details
1968 Volume 28 Issue 12 Pages 752-760
Mucoid M of Escherichia as well as Salmonella can be originated from Murase's M and forms a large mucoid colony of 2.5-5 mm in diameter on Galactose agar plate usually, but a non-mucoid, dwarf colony of 0.5-0.9 mm in diameter on plain agar plate. Many hitherto unknown points to us about Mucoid M were clarified. The results obtained were as follows :
1) Mucoid M is slightly more resistant to Galactose than M, when measured by cup-plate method.
2) Mucoid M lacks in motility being different from the original wild type.
3) Mucoid M shows no reaction in the acid agglutination test at pH value 2.35-4.90 (Galactose mucoid phase) .
4) Mucoid M is nearly constantly sensitive to 0.5-1 % Na2SO3 (cup-plate method) and forms an inhibition zone.
5) Mucoid M ferments many kinds of carbohydrates quite in the similar manner to M, but without gas (E. coli and Salm, typhi-murium) except in the case of Salm. enteritidis.
6) Volume of mucoid colony was about ten times larger than that of dwarf colony. But live organisms contained in each colony were equal in number. From these findings, it appeared that the factor which caused a difference in the size of colony was not the rate of growth, but was the size of each individual bacillus. So, Mucoid M was designated as DMl and the mucoid colony induced by Galactose was named as Galactose mucoid phase of DM1.
7) Mucoid capsule was recognized within 40 minutes after spreading Galactose linearly near the dwarf colonies cultured one night on plain agar plate. Enlargement and mucoid forma-tion of the colony were recognized distinctly within 2 hours.
8) Dwarf and Galactose resistant mutant was constantly recovered from the old culture of Galactose peptone water.
